Vehicles have utilized vacuum generated in the intake system to assist in operation of various engine systems such as braking systems, cruise control systems, exhaust gas recirculation (EGR) systems, etc. For instance, vacuum may be used for brake boost to amplify the driver's brake pedal input, enabling a reduction in the driver's braking effort. However, fuel efficiency standards, turbochargers, etc., have led to the downsizing of some vehicle engines, resulting in a reduced ability to provide vacuum to auxiliary vehicle systems from the intake manifold. To cope with the drop in vacuum levels, aspirators have been used in engines to charge vacuum reservoirs that provide a vacuum reserve from which auxiliary vehicle systems can draw from.
Previous aspirator designs have routed airflow to and from the aspirator via external hoses. The inventors have recognized several drawbacks with this type of aspirator design and other prior aspirator designs. The external routing of aspirator hoses increases the bulkiness of the vacuum system. As such, the engine may not be able to meet packaging constraints in some vehicles, such as vehicles where space is at a premium. Furthermore, the external hoses may be susceptible to damage during engine manufacturing and maintenance. Damage to the hoses can cause leaks that can diminish the aspirator's ability to generate a vacuum or render the aspirator inoperable, in some cases. The externally routed hoses may also experience significant flow losses due to the length and contours of the hoses, thereby reducing the system's efficiency.
The inventors have recognized the aforementioned drawbacks and facing these challenges developed a vacuum system. The vacuum system includes, in one example, a vacuum aspirator coupled to a housing of an intake manifold, the vacuum aspirator including an air intake port, a vacuum port, and a manifold port. The vacuum system also includes a manifold vacuum passage and a vacuum reservoir passage traversing the housing of the intake manifold, the manifold vacuum passage coupled to the manifold port and the vacuum reservoir passage coupled to the vacuum port. Routing the vacuum reservoir passage and the manifold vacuum passage through the intake manifold housing enables the system to achieve space saving gains through a reduction in the profile of the vacuum system. Additionally, internal routing of the vacuum reservoir passage and the manifold vacuum passage facilitates an increase in the durability of the vacuum system and a reduction in the likelihood of component damage during manufacturing, repair, and maintenance, when compared to previous engine systems. Flow losses in the vacuum system may also be diminished through a reduction in the length manifold vacuum conduit when compared to systems with externally routed hoses providing fluidic connection between the intake manifold and an aspirator.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.